Last year, this website reported VBZ's plans to test energy storage using a flywheel installation by the Zoo terminus. Evaluation of the six-week trial showed that currently about 85% of regenerated energy is re-used by trams. Additional energy savings made through the storage were negated by the enery costs of actually running the installation and its internal losses. The technology is not totally unsuitable, however, as VBZ believes it could be useful for supporting the power supply on heavily used sections of line.